Anyone ever have their fuel pump resistor relay on their S4 TII go bad? I'm wondering what the symptoms of that would be like, if anyone knows... thanks

 

The system is fail-safe, so if the relay stops working or the ECU stops sending a signal, the fuel pump will receive full battery voltage all the time. This would cause you to run rich most of the time, since full voltage is normally only used under full load.

 

Hmm, ok... do you happen to know what deviation from the FSM resistances would constitute a failure of the resistor relay? Mine are slightly off.

FSM:
A-B = 0 ohm
C-D = 60ish-90ish ohms (can't remember exactly)
E-F = 0.64 ohm

Mine:
A-B = 0.8 ohm
C-D = 70ish ohms
E-F = 0.2 ohm

In other words, does that make mine broken?

 

i think yours are ok, generally the resistance ranges are broader than what mazda says

mike

 

It's just a relay. Put 12V across the coil's terminals and if it clicks, it works.